Asphalt has been employed for numerous and wide variety of applications for many years. One of the problems encountered with asphalt is that its adhesion to various substrates and especially to aggregate needs to be improved. Other deficiencies in the properties of unmodified asphalt which are satisfied by the composition of the present invention include poor strength, low temperature brittleness, poor adhesion, excessive flow at high temperatures, variability in properties and poor coating of wet surfaces.
Thus, in accordance with the present invention, there is provided an improved asphalt composition which is a blend of two chemically modified asphalt compositions. The first chemically modified asphalt composition is the product produced by reacting asphalt with a vinyl aromatic monomer and an amine of an acyclic unsaturated hydrocarbon, and the second chemically modified asphalt is the product produced by reacting asphalt with a vinyl aromatic monomer and a rubbery polymer.
While the chemically modified asphalt product produced by reacting asphalt with a vinyl aromatic monomer and an amine of an acyclic unsaturated hydrocarbon has many desirably properties, it needs to be improved with respect to providing more flexibility and durability, higher strength and better high temperature flow properties. By blending with the above chemically modified asphalt, a chemically modified asphalt product produced by reacting asphalt with a vinyl aromatic monomer and a rubbery polymer, the blended composition has increased flexibility, improved strength, reduced high temperature flow, increased durability, and improved compatibility with polymers. These compositions will find utility for a wide variety of purposes. They, for example, will find application in the highway and bridge construction repair and maintenance areas as, for example, crack and pothole fillers, joint sealers, and water resistant membranes, and as cut-backs with the compositions being used alone or, if desired, further blended with conventional asphalts. These compositions can be formed into emulsions either with or without emulsifiers to form a rapid set emulsion, having utility for chip and seal applications, or as a cold overlay. Generally, it will be preferred to use conventional emulsifiers in forming such emulsions, and most desirably, non-ionic surfactants. The compositions may also be employed as corrosion resistant and/or water resistant coatings for metals and as coatings and/or impregnants for glass, especially glass fibers. Such coated or impregnated glass fibers will show outstanding compatibility with conventional asphalt and consequently will serve as outstanding reinforcements for such asphalts.